German submarine U-665

German submarine U-665 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 10 June 1941 by Deutsche Werft, Hamburg as yard number 814, launched on 9 June 1942 and commissioned on 22 July 1942 under Leutnant zur See Hans-Jürgen Haupt.

Design
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-665 had a displacement of 769 t when at the surface and 871 t while submerged. She had a total length of 67.10 m, a pressure hull length of 50.50 m, a beam of 6.20 m, a height of 9.60 m, and a draught of 4.74 m. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2800 to 3200 PS for use while surfaced, two Siemens-Schuckert GU 343/38–8 double-acting electric motors producing a total of 750 PS for use while submerged. She had two shafts and two 1.23 m propellers. The boat was capable of operating at depths of up to 230 m.

The submarine had a maximum surface speed of 17.7 kn and a maximum submerged speed of 7.6 kn. When submerged, the boat could operate for 80 nmi at 4 kn; when surfaced, she could travel 8500 nmi at 10 kn. U-665 was fitted with five 53.3 cm torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm SK C/35 naval gun, 220 rounds, and two twin 2 cm C/30 anti-aircraft guns. The boat had a complement of between forty-four and sixty.

Service history
The boat's career began with training at 5th U-boat Flotilla on 22 July 1942, followed by active service on 1 February 1943 as part of the 1st Flotilla for the remainder of her short service. In her sole patrol she sank one merchant ship, for a total of.

Wolfpacks
U-665 took part in three wolfpacks, namely:
 * Neuland (4 – 6 March 1943)
 * Ostmark (6 – 11 March 1943)
 * Stürmer (11 – 20 March 1943)

Fate
U-665 has been missing since 22 March 1943 in the Bay of Biscay, west of La Pallice.

Previously recorded fate
U-665 was thought to have been sunk on 22 March 1943 in the Bay of Biscay west of Nantes at 46.78333°N, -9.96667°W, by depth charges from Vickers Wellington aircraft of No. 172 Squadron RAF (call-sign G). This attack was actually against U-448, inflicting no damage.

U-665 was also thought to have been sunk on 22 March 1943 in the North Atlantic at 48.06667°N, -10.43333°W, by depth charges from an Armstrong Whitworth Whitley VII of No. 10 Operational Training Unit RAF (10 OTU) (call-sign Q), for the loss of all hands.